[Spheres from the oocyte nuclei of the house cricket and the damselfly contain pre-mRNA splicing and pre-rRNA processing factors].

By the method of immunocytochemistry it has been shown that spheres from cricket and damselfly oocyte nuclei contain small nuclear RNA (snRNA) and fibrillarin, a protein involved in pre-rRNA processing. Besides, in cricket oocyte spheres coilin has been revealed, a protein which is part of intranuclear structures in somatic cells called coiled bodies. By the method of nucleic acid hybridization in situ, U1, U2 and U6 snRNAs were identified in spheres of cricket oocytes.

[The formation of the karyosphere in the oogenesis of insects and amphibians].

This review deals with the authors' own and literary data on the ultrastructural and cytochemical organization of insect and amphibian oocyte nuclei, with special attention being paid to the karyosphere and its capsule. The evidence provided is supplemented with data on isolated karyospheres in Rana temporaria oocytes. A conclusion is made that the karyosphere is a complex structure which contains all chromosomes in the limited space of the oocyte nucleus, and that these chromosomes are, as a rule, in the process of inactivation.

Human antral follicles: oocyte nucleus and the karyosphere formation (electron microscopic and autoradiographic data).

The functional organization of the nucleus in the oocytes from human antral follicles was examined by morphological and autoradiographic analysis methods at the light and electron microscopic level. According to the position of the nucleus, the level of its transcriptional activity, and the pattern of distribution of structures in it, oocytes fall into two groups. In the first one, the oocytes with the nucleus in the central position are characterized by the distribution of numerous structures all over the nucleus or by a different extent of aggregation of chromatin around the nucleolus.

[Nucleoli and nucleolus-like bodies in oogenesis stained by silver nitrate].

The nuclear structures were studied in oocytes of two frog species (Rana temporaria and R. ridibunda) in oocytes and trophocytes of three insect species (Blaps lethifera, Laspeyresia pomonella and Chrysopa perla) by the AgNO3-staining method (Howell, Black, 1980). The previously investigated nucleoli of the insect trophocytes and the extra-r-DNA bodies of Chrysopa oocytes were used as test objects.